In certain applications, such as, for example, a fuel pump for an aircraft, it is desirable to vary an output pressure and flow of a centrifugal pump independently of the speed.
In aircraft fuel pumps, it is a conventional practice to throttle, recirculate or bypass the flow of the pump so as to vary the output pressure and flow thereof; however, this conventional approach results in unacceptable fuel temperature rise due to the poor efficiency of the approach and results in high power dissipation of the required flow controlling means.
Various pumps or pump-like arrangements utilizing a pitot tube or similar element have been proposed in, for example, U.S. Pat. Nos. 2,440,624, 3,791,757, 3,930,744, 4,267,964, 4,281,962, 4,339,923 and Austrian Patent 230,159.
While the above proposed constructions provide diverse technical approaches for pumps or liquid handling arrangements, none of the proposed constructions are suitable for use as, for example, an aircraft fuel pump nor capable of varying an output pressure and flow of the centrifugal pump independently of the speed thereof.